Microsoft has paused distributing its Meltdown and Spectre security updates for AMD machines after reports of PCs not booting. Microsoft’s support forums have been full of complaints from PC owners with AMD processors, and the software giant has acknowledged the issues today. Microsoft is blaming AMD’s documentation for the unexpected problems.

“Microsoft has reports of customers with some AMD devices getting into an unbootable state after installing recent Windows operating system security updates,” says a Microsoft spokesperson. “After investigating, Microsoft has determined that some AMD chipsets do not conform to the documentation previously provided to Microsoft to develop the Windows operating system mitigations to protect against the chipset vulnerabilities known as Spectre and Meltdown.”